Regular expression for validating numbers
Eventually, Ken Thompson built support for regular expressions into qed and grep, both very popular text utilities.
NET Regular Expression API Free Tools Advanced Topics Conclusion Resources About the Author Support for regular expressions in the Microsoft®.NET Framework is first-class, and even just within Microsoft® ASP.NET there are controls that rely on the language of regular expressions.This article covers the basics and recommends where to go to learn more. I hope it will also make a handy reference/refresher for developers who have used regular expressions before, in conjunction with my regular expression cheat sheet. (14 printed pages) Download the source code for this article. Whether you need to validate user input, search for patterns within strings, or reformat text in powerful ways, regular expressions can help.
NET Regular Expression API Summary: Regular expressions are an extremely useful tool for working with text.
Introduction Brief History of Regular Expressions Simple Expressions Quantifiers Metacharacters Character Classes Predefined Set Metacharacters Sample Expressions Validation in ASP.
This article is designed for beginners with little or no experience with regular expressions, but who are familiar with ASP. In this article, I will discuss: If you have questions about this article or regular expressions in general, I invite you to ask them on the regex mailing list at which as I'm writing this has over 350 subscribers.
Regular expressions as they exist today were invented in the 1950s.
Regular expressions were originally used to describe "regular sets," which were patterns under study by neurophysiologists.
Credit for the first regular expressions is given to the mathematician Stephen Kleene.